1 // Copyright 2012-2015 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
15 use rustc::middle::cstore::{LinkMeta, LinkagePreference, NativeLibrary,
16 EncodedMetadata, EncodedMetadataHash};
17 use rustc::hir::def_id::{CrateNum, CRATE_DEF_INDEX, DefIndex, DefId};
18 use rustc::hir::map::definitions::DefPathTable;
19 use rustc::middle::dependency_format::Linkage;
20 use rustc::middle::lang_items;
22 use rustc::traits::specialization_graph;
23 use rustc::ty::{self, Ty, TyCtxt, ReprOptions};
25 use rustc::session::config::{self, CrateTypeProcMacro};
26 use rustc::util::nodemap::{FxHashMap, NodeSet};
28 use rustc_serialize::{Encodable, Encoder, SpecializedEncoder, opaque};
31 use std::io::prelude::*;
35 use syntax::ast::{self, CRATE_NODE_ID};
36 use syntax::codemap::Spanned;
38 use syntax::symbol::Symbol;
39 use syntax_pos::{self, DUMMY_SP};
41 use rustc::hir::{self, PatKind};
42 use rustc::hir::itemlikevisit::ItemLikeVisitor;
43 use rustc::hir::intravisit::{Visitor, NestedVisitorMap};
44 use rustc::hir::intravisit;
46 use super::index_builder::{FromId, IndexBuilder, Untracked, EntryBuilder};
48 pub struct EncodeContext<'a, 'tcx: 'a> {
49 opaque: opaque::Encoder<'a>,
50 pub tcx: TyCtxt<'a, 'tcx, 'tcx>,
51 link_meta: &'a LinkMeta,
52 cstore: &'a cstore::CStore,
53 exported_symbols: &'a NodeSet,
55 lazy_state: LazyState,
56 type_shorthands: FxHashMap<Ty<'tcx>, usize>,
57 predicate_shorthands: FxHashMap<ty::Predicate<'tcx>, usize>,
59 pub metadata_hashes: Vec<EncodedMetadataHash>,
62 macro_rules! encoder_methods {
63 ($($name:ident($ty:ty);)*) => {
64 $(fn $name(&mut self, value: $ty) -> Result<(), Self::Error> {
65 self.opaque.$name(value)
70 impl<'a, 'tcx> Encoder for EncodeContext<'a, 'tcx> {
71 type Error = <opaque::Encoder<'a> as Encoder>::Error;
73 fn emit_nil(&mut self) -> Result<(), Self::Error> {
100 impl<'a, 'tcx, T> SpecializedEncoder<Lazy<T>> for EncodeContext<'a, 'tcx> {
101 fn specialized_encode(&mut self, lazy: &Lazy<T>) -> Result<(), Self::Error> {
102 self.emit_lazy_distance(lazy.position, Lazy::<T>::min_size())
106 impl<'a, 'tcx, T> SpecializedEncoder<LazySeq<T>> for EncodeContext<'a, 'tcx> {
107 fn specialized_encode(&mut self, seq: &LazySeq<T>) -> Result<(), Self::Error> {
108 self.emit_usize(seq.len)?;
112 self.emit_lazy_distance(seq.position, LazySeq::<T>::min_size(seq.len))
116 impl<'a, 'tcx> SpecializedEncoder<Ty<'tcx>> for EncodeContext<'a, 'tcx> {
117 fn specialized_encode(&mut self, ty: &Ty<'tcx>) -> Result<(), Self::Error> {
118 self.encode_with_shorthand(ty, &ty.sty, |ecx| &mut ecx.type_shorthands)
122 impl<'a, 'tcx> SpecializedEncoder<ty::GenericPredicates<'tcx>> for EncodeContext<'a, 'tcx> {
123 fn specialized_encode(&mut self,
124 predicates: &ty::GenericPredicates<'tcx>)
125 -> Result<(), Self::Error> {
126 predicates.parent.encode(self)?;
127 predicates.predicates.len().encode(self)?;
128 for predicate in &predicates.predicates {
129 self.encode_with_shorthand(predicate, predicate, |ecx| &mut ecx.predicate_shorthands)?
135 impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
136 pub fn position(&self) -> usize {
137 self.opaque.position()
140 fn emit_node<F: FnOnce(&mut Self, usize) -> R, R>(&mut self, f: F) -> R {
141 assert_eq!(self.lazy_state, LazyState::NoNode);
142 let pos = self.position();
143 self.lazy_state = LazyState::NodeStart(pos);
144 let r = f(self, pos);
145 self.lazy_state = LazyState::NoNode;
149 fn emit_lazy_distance(&mut self,
152 -> Result<(), <Self as Encoder>::Error> {
153 let min_end = position + min_size;
154 let distance = match self.lazy_state {
155 LazyState::NoNode => bug!("emit_lazy_distance: outside of a metadata node"),
156 LazyState::NodeStart(start) => {
157 assert!(min_end <= start);
160 LazyState::Previous(last_min_end) => {
161 assert!(last_min_end <= position);
162 position - last_min_end
165 self.lazy_state = LazyState::Previous(min_end);
166 self.emit_usize(distance)
169 pub fn lazy<T: Encodable>(&mut self, value: &T) -> Lazy<T> {
170 self.emit_node(|ecx, pos| {
171 value.encode(ecx).unwrap();
173 assert!(pos + Lazy::<T>::min_size() <= ecx.position());
174 Lazy::with_position(pos)
178 pub fn lazy_seq<I, T>(&mut self, iter: I) -> LazySeq<T>
179 where I: IntoIterator<Item = T>,
182 self.emit_node(|ecx, pos| {
183 let len = iter.into_iter().map(|value| value.encode(ecx).unwrap()).count();
185 assert!(pos + LazySeq::<T>::min_size(len) <= ecx.position());
186 LazySeq::with_position_and_length(pos, len)
190 pub fn lazy_seq_ref<'b, I, T>(&mut self, iter: I) -> LazySeq<T>
191 where I: IntoIterator<Item = &'b T>,
194 self.emit_node(|ecx, pos| {
195 let len = iter.into_iter().map(|value| value.encode(ecx).unwrap()).count();
197 assert!(pos + LazySeq::<T>::min_size(len) <= ecx.position());
198 LazySeq::with_position_and_length(pos, len)
202 /// Encode the given value or a previously cached shorthand.
203 fn encode_with_shorthand<T, U, M>(&mut self,
207 -> Result<(), <Self as Encoder>::Error>
208 where M: for<'b> Fn(&'b mut Self) -> &'b mut FxHashMap<T, usize>,
209 T: Clone + Eq + Hash,
212 let existing_shorthand = map(self).get(value).cloned();
213 if let Some(shorthand) = existing_shorthand {
214 return self.emit_usize(shorthand);
217 let start = self.position();
218 variant.encode(self)?;
219 let len = self.position() - start;
221 // The shorthand encoding uses the same usize as the
222 // discriminant, with an offset so they can't conflict.
223 let discriminant = unsafe { intrinsics::discriminant_value(variant) };
224 assert!(discriminant < SHORTHAND_OFFSET as u64);
225 let shorthand = start + SHORTHAND_OFFSET;
227 // Get the number of bits that leb128 could fit
228 // in the same space as the fully encoded type.
229 let leb128_bits = len * 7;
231 // Check that the shorthand is a not longer than the
232 // full encoding itself, i.e. it's an obvious win.
233 if leb128_bits >= 64 || (shorthand as u64) < (1 << leb128_bits) {
234 map(self).insert(value.clone(), shorthand);
241 impl<'a, 'b: 'a, 'tcx: 'b> EntryBuilder<'a, 'b, 'tcx> {
242 fn encode_item_variances(&mut self, def_id: DefId) -> LazySeq<ty::Variance> {
243 debug!("EntryBuilder::encode_item_variances({:?})", def_id);
245 self.lazy_seq_from_slice(&tcx.item_variances(def_id))
248 fn encode_item_type(&mut self, def_id: DefId) -> Lazy<Ty<'tcx>> {
250 let ty = tcx.item_type(def_id);
251 debug!("EntryBuilder::encode_item_type({:?}) => {:?}", def_id, ty);
255 /// Encode data for the given variant of the given ADT. The
256 /// index of the variant is untracked: this is ok because we
257 /// will have to lookup the adt-def by its id, and that gives us
258 /// the right to access any information in the adt-def (including,
259 /// e.g., the length of the various vectors).
260 fn encode_enum_variant_info(&mut self,
261 (enum_did, Untracked(index)): (DefId, Untracked<usize>))
264 let def = tcx.lookup_adt_def(enum_did);
265 let variant = &def.variants[index];
266 let def_id = variant.did;
267 debug!("EntryBuilder::encode_enum_variant_info({:?})", def_id);
269 let data = VariantData {
270 ctor_kind: variant.ctor_kind,
271 discr: variant.discr,
272 evaluated_discr: match variant.discr {
273 ty::VariantDiscr::Explicit(def_id) => {
274 ty::queries::monomorphic_const_eval::get(tcx, DUMMY_SP, def_id).ok()
276 ty::VariantDiscr::Relative(_) => None
281 let enum_id = tcx.hir.as_local_node_id(enum_did).unwrap();
282 let enum_vis = &tcx.hir.expect_item(enum_id).vis;
285 kind: EntryKind::Variant(self.lazy(&data)),
286 visibility: self.lazy(&ty::Visibility::from_hir(enum_vis, enum_id, tcx)),
287 span: self.lazy(&tcx.def_span(def_id)),
288 attributes: self.encode_attributes(&tcx.get_attrs(def_id)),
289 children: self.lazy_seq(variant.fields.iter().map(|f| {
290 assert!(f.did.is_local());
293 stability: self.encode_stability(def_id),
294 deprecation: self.encode_deprecation(def_id),
296 ty: Some(self.encode_item_type(def_id)),
297 inherent_impls: LazySeq::empty(),
298 variances: LazySeq::empty(),
299 generics: Some(self.encode_generics(def_id)),
300 predicates: Some(self.encode_predicates(def_id)),
303 mir: self.encode_mir(def_id),
307 fn encode_info_for_mod(&mut self,
308 FromId(id, (md, attrs, vis)): FromId<(&hir::Mod,
313 let def_id = tcx.hir.local_def_id(id);
314 debug!("EntryBuilder::encode_info_for_mod({:?})", def_id);
317 reexports: match tcx.export_map.get(&id) {
318 Some(exports) if *vis == hir::Public => {
319 self.lazy_seq_from_slice(exports.as_slice())
321 _ => LazySeq::empty(),
326 kind: EntryKind::Mod(self.lazy(&data)),
327 visibility: self.lazy(&ty::Visibility::from_hir(vis, id, tcx)),
328 span: self.lazy(&md.inner),
329 attributes: self.encode_attributes(attrs),
330 children: self.lazy_seq(md.item_ids.iter().map(|item_id| {
331 tcx.hir.local_def_id(item_id.id).index
333 stability: self.encode_stability(def_id),
334 deprecation: self.encode_deprecation(def_id),
337 inherent_impls: LazySeq::empty(),
338 variances: LazySeq::empty(),
348 impl<'a, 'b, 'tcx> IndexBuilder<'a, 'b, 'tcx> {
349 fn encode_fields(&mut self, adt_def_id: DefId) {
350 let def = self.tcx.lookup_adt_def(adt_def_id);
351 for (variant_index, variant) in def.variants.iter().enumerate() {
352 for (field_index, field) in variant.fields.iter().enumerate() {
353 self.record(field.did,
354 EntryBuilder::encode_field,
355 (adt_def_id, Untracked((variant_index, field_index))));
361 impl<'a, 'b: 'a, 'tcx: 'b> EntryBuilder<'a, 'b, 'tcx> {
362 /// Encode data for the given field of the given variant of the
363 /// given ADT. The indices of the variant/field are untracked:
364 /// this is ok because we will have to lookup the adt-def by its
365 /// id, and that gives us the right to access any information in
366 /// the adt-def (including, e.g., the length of the various
368 fn encode_field(&mut self,
369 (adt_def_id, Untracked((variant_index, field_index))): (DefId,
374 let variant = &tcx.lookup_adt_def(adt_def_id).variants[variant_index];
375 let field = &variant.fields[field_index];
377 let def_id = field.did;
378 debug!("EntryBuilder::encode_field({:?})", def_id);
380 let variant_id = tcx.hir.as_local_node_id(variant.did).unwrap();
381 let variant_data = tcx.hir.expect_variant_data(variant_id);
384 kind: EntryKind::Field,
385 visibility: self.lazy(&field.vis),
386 span: self.lazy(&tcx.def_span(def_id)),
387 attributes: self.encode_attributes(&variant_data.fields()[field_index].attrs),
388 children: LazySeq::empty(),
389 stability: self.encode_stability(def_id),
390 deprecation: self.encode_deprecation(def_id),
392 ty: Some(self.encode_item_type(def_id)),
393 inherent_impls: LazySeq::empty(),
394 variances: LazySeq::empty(),
395 generics: Some(self.encode_generics(def_id)),
396 predicates: Some(self.encode_predicates(def_id)),
403 fn encode_struct_ctor(&mut self, (adt_def_id, def_id): (DefId, DefId)) -> Entry<'tcx> {
404 debug!("EntryBuilder::encode_struct_ctor({:?})", def_id);
406 let variant = tcx.lookup_adt_def(adt_def_id).struct_variant();
408 let data = VariantData {
409 ctor_kind: variant.ctor_kind,
410 discr: variant.discr,
411 evaluated_discr: None,
412 struct_ctor: Some(def_id.index),
415 let struct_id = tcx.hir.as_local_node_id(adt_def_id).unwrap();
416 let struct_vis = &tcx.hir.expect_item(struct_id).vis;
417 let mut ctor_vis = ty::Visibility::from_hir(struct_vis, struct_id, tcx);
418 for field in &variant.fields {
419 if ctor_vis.is_at_least(field.vis, tcx) {
420 ctor_vis = field.vis;
424 let repr_options = get_repr_options(&tcx, adt_def_id);
427 kind: EntryKind::Struct(self.lazy(&data), repr_options),
428 visibility: self.lazy(&ctor_vis),
429 span: self.lazy(&tcx.def_span(def_id)),
430 attributes: LazySeq::empty(),
431 children: LazySeq::empty(),
432 stability: self.encode_stability(def_id),
433 deprecation: self.encode_deprecation(def_id),
435 ty: Some(self.encode_item_type(def_id)),
436 inherent_impls: LazySeq::empty(),
437 variances: LazySeq::empty(),
438 generics: Some(self.encode_generics(def_id)),
439 predicates: Some(self.encode_predicates(def_id)),
442 mir: self.encode_mir(def_id),
446 fn encode_generics(&mut self, def_id: DefId) -> Lazy<ty::Generics> {
447 debug!("EntryBuilder::encode_generics({:?})", def_id);
449 self.lazy(tcx.item_generics(def_id))
452 fn encode_predicates(&mut self, def_id: DefId) -> Lazy<ty::GenericPredicates<'tcx>> {
453 debug!("EntryBuilder::encode_predicates({:?})", def_id);
455 self.lazy(&tcx.item_predicates(def_id))
458 fn encode_info_for_trait_item(&mut self, def_id: DefId) -> Entry<'tcx> {
459 debug!("EntryBuilder::encode_info_for_trait_item({:?})", def_id);
462 let node_id = tcx.hir.as_local_node_id(def_id).unwrap();
463 let ast_item = tcx.hir.expect_trait_item(node_id);
464 let trait_item = tcx.associated_item(def_id);
466 let container = match trait_item.defaultness {
467 hir::Defaultness::Default { has_value: true } =>
468 AssociatedContainer::TraitWithDefault,
469 hir::Defaultness::Default { has_value: false } =>
470 AssociatedContainer::TraitRequired,
471 hir::Defaultness::Final =>
472 span_bug!(ast_item.span, "traits cannot have final items"),
475 let kind = match trait_item.kind {
476 ty::AssociatedKind::Const => {
477 EntryKind::AssociatedConst(container, 0)
479 ty::AssociatedKind::Method => {
480 let fn_data = if let hir::TraitItemKind::Method(_, ref m) = ast_item.node {
481 let arg_names = match *m {
482 hir::TraitMethod::Required(ref names) => {
483 self.encode_fn_arg_names(names)
485 hir::TraitMethod::Provided(body) => {
486 self.encode_fn_arg_names_for_body(body)
490 constness: hir::Constness::NotConst,
496 EntryKind::Method(self.lazy(&MethodData {
498 container: container,
499 has_self: trait_item.method_has_self_argument,
502 ty::AssociatedKind::Type => EntryKind::AssociatedType(container),
507 visibility: self.lazy(&trait_item.vis),
508 span: self.lazy(&ast_item.span),
509 attributes: self.encode_attributes(&ast_item.attrs),
510 children: LazySeq::empty(),
511 stability: self.encode_stability(def_id),
512 deprecation: self.encode_deprecation(def_id),
514 ty: match trait_item.kind {
515 ty::AssociatedKind::Const |
516 ty::AssociatedKind::Method => {
517 Some(self.encode_item_type(def_id))
519 ty::AssociatedKind::Type => {
520 if trait_item.defaultness.has_value() {
521 Some(self.encode_item_type(def_id))
527 inherent_impls: LazySeq::empty(),
528 variances: LazySeq::empty(),
529 generics: Some(self.encode_generics(def_id)),
530 predicates: Some(self.encode_predicates(def_id)),
532 ast: if let hir::TraitItemKind::Const(_, Some(body)) = ast_item.node {
533 Some(self.encode_body(body))
537 mir: self.encode_mir(def_id),
541 fn encode_info_for_impl_item(&mut self, def_id: DefId) -> Entry<'tcx> {
542 debug!("EntryBuilder::encode_info_for_impl_item({:?})", def_id);
543 let node_id = self.tcx.hir.as_local_node_id(def_id).unwrap();
544 let ast_item = self.tcx.hir.expect_impl_item(node_id);
545 let impl_item = self.tcx.associated_item(def_id);
547 let container = match impl_item.defaultness {
548 hir::Defaultness::Default { has_value: true } => AssociatedContainer::ImplDefault,
549 hir::Defaultness::Final => AssociatedContainer::ImplFinal,
550 hir::Defaultness::Default { has_value: false } =>
551 span_bug!(ast_item.span, "impl items always have values (currently)"),
554 let kind = match impl_item.kind {
555 ty::AssociatedKind::Const => {
556 EntryKind::AssociatedConst(container,
557 ty::queries::mir_const_qualif::get(self.tcx, ast_item.span, def_id))
559 ty::AssociatedKind::Method => {
560 let fn_data = if let hir::ImplItemKind::Method(ref sig, body) = ast_item.node {
562 constness: sig.constness,
563 arg_names: self.encode_fn_arg_names_for_body(body),
568 EntryKind::Method(self.lazy(&MethodData {
570 container: container,
571 has_self: impl_item.method_has_self_argument,
574 ty::AssociatedKind::Type => EntryKind::AssociatedType(container)
577 let (ast, mir) = if let hir::ImplItemKind::Const(_, body) = ast_item.node {
579 } else if let hir::ImplItemKind::Method(ref sig, body) = ast_item.node {
580 let generics = self.tcx.item_generics(def_id);
581 let types = generics.parent_types as usize + generics.types.len();
582 let needs_inline = types > 0 || attr::requests_inline(&ast_item.attrs);
583 let is_const_fn = sig.constness == hir::Constness::Const;
584 let ast = if is_const_fn { Some(body) } else { None };
585 let always_encode_mir = self.tcx.sess.opts.debugging_opts.always_encode_mir;
586 (ast, needs_inline || is_const_fn || always_encode_mir)
593 visibility: self.lazy(&impl_item.vis),
594 span: self.lazy(&ast_item.span),
595 attributes: self.encode_attributes(&ast_item.attrs),
596 children: LazySeq::empty(),
597 stability: self.encode_stability(def_id),
598 deprecation: self.encode_deprecation(def_id),
600 ty: Some(self.encode_item_type(def_id)),
601 inherent_impls: LazySeq::empty(),
602 variances: LazySeq::empty(),
603 generics: Some(self.encode_generics(def_id)),
604 predicates: Some(self.encode_predicates(def_id)),
606 ast: ast.map(|body| self.encode_body(body)),
607 mir: if mir { self.encode_mir(def_id) } else { None },
611 fn encode_fn_arg_names_for_body(&mut self, body_id: hir::BodyId)
612 -> LazySeq<ast::Name> {
613 let _ignore = self.tcx.dep_graph.in_ignore();
614 let body = self.tcx.hir.body(body_id);
615 self.lazy_seq(body.arguments.iter().map(|arg| {
617 PatKind::Binding(_, _, name, _) => name.node,
618 _ => Symbol::intern("")
623 fn encode_fn_arg_names(&mut self, names: &[Spanned<ast::Name>])
624 -> LazySeq<ast::Name> {
625 self.lazy_seq(names.iter().map(|name| name.node))
628 fn encode_mir(&mut self, def_id: DefId) -> Option<Lazy<mir::Mir<'tcx>>> {
629 debug!("EntryBuilder::encode_mir({:?})", def_id);
630 self.tcx.maps.mir.borrow().get(&def_id).map(|mir| self.lazy(&*mir.borrow()))
633 // Encodes the inherent implementations of a structure, enumeration, or trait.
634 fn encode_inherent_implementations(&mut self, def_id: DefId) -> LazySeq<DefIndex> {
635 debug!("EntryBuilder::encode_inherent_implementations({:?})", def_id);
636 match self.tcx.maps.inherent_impls.borrow().get(&def_id) {
637 None => LazySeq::empty(),
638 Some(implementations) => {
639 self.lazy_seq(implementations.iter().map(|&def_id| {
640 assert!(def_id.is_local());
647 fn encode_stability(&mut self, def_id: DefId) -> Option<Lazy<attr::Stability>> {
648 debug!("EntryBuilder::encode_stability({:?})", def_id);
649 self.tcx.lookup_stability(def_id).map(|stab| self.lazy(stab))
652 fn encode_deprecation(&mut self, def_id: DefId) -> Option<Lazy<attr::Deprecation>> {
653 debug!("EntryBuilder::encode_deprecation({:?})", def_id);
654 self.tcx.lookup_deprecation(def_id).map(|depr| self.lazy(&depr))
657 fn encode_info_for_item(&mut self, (def_id, item): (DefId, &'tcx hir::Item)) -> Entry<'tcx> {
660 debug!("EntryBuilder::encode_info_for_item({:?})", def_id);
662 let kind = match item.node {
663 hir::ItemStatic(_, hir::MutMutable, _) => EntryKind::MutStatic,
664 hir::ItemStatic(_, hir::MutImmutable, _) => EntryKind::ImmStatic,
665 hir::ItemConst(..) => {
666 EntryKind::Const(ty::queries::mir_const_qualif::get(tcx, item.span, def_id))
668 hir::ItemFn(_, _, constness, .., body) => {
670 constness: constness,
671 arg_names: self.encode_fn_arg_names_for_body(body),
674 EntryKind::Fn(self.lazy(&data))
676 hir::ItemMod(ref m) => {
677 return self.encode_info_for_mod(FromId(item.id, (m, &item.attrs, &item.vis)));
679 hir::ItemForeignMod(_) => EntryKind::ForeignMod,
680 hir::ItemTy(..) => EntryKind::Type,
681 hir::ItemEnum(..) => EntryKind::Enum(get_repr_options(&tcx, def_id)),
682 hir::ItemStruct(ref struct_def, _) => {
683 let variant = tcx.lookup_adt_def(def_id).struct_variant();
685 // Encode def_ids for each field and method
686 // for methods, write all the stuff get_trait_method
688 let struct_ctor = if !struct_def.is_struct() {
689 Some(tcx.hir.local_def_id(struct_def.id()).index)
694 let repr_options = get_repr_options(&tcx, def_id);
696 EntryKind::Struct(self.lazy(&VariantData {
697 ctor_kind: variant.ctor_kind,
698 discr: variant.discr,
699 evaluated_discr: None,
700 struct_ctor: struct_ctor,
703 hir::ItemUnion(..) => {
704 let variant = tcx.lookup_adt_def(def_id).struct_variant();
705 let repr_options = get_repr_options(&tcx, def_id);
707 EntryKind::Union(self.lazy(&VariantData {
708 ctor_kind: variant.ctor_kind,
709 discr: variant.discr,
710 evaluated_discr: None,
714 hir::ItemDefaultImpl(..) => {
715 let data = ImplData {
716 polarity: hir::ImplPolarity::Positive,
718 coerce_unsized_info: None,
719 trait_ref: tcx.impl_trait_ref(def_id).map(|trait_ref| self.lazy(&trait_ref)),
722 EntryKind::DefaultImpl(self.lazy(&data))
724 hir::ItemImpl(_, polarity, ..) => {
725 let trait_ref = tcx.impl_trait_ref(def_id);
726 let parent = if let Some(trait_ref) = trait_ref {
727 let trait_def = tcx.lookup_trait_def(trait_ref.def_id);
728 trait_def.ancestors(def_id).skip(1).next().and_then(|node| {
730 specialization_graph::Node::Impl(parent) => Some(parent),
738 // if this is an impl of `CoerceUnsized`, create its
739 // "unsized info", else just store None
740 let coerce_unsized_info =
741 trait_ref.and_then(|t| {
742 if Some(t.def_id) == tcx.lang_items.coerce_unsized_trait() {
743 Some(ty::queries::coerce_unsized_info::get(tcx, item.span, def_id))
749 let data = ImplData {
752 coerce_unsized_info: coerce_unsized_info,
753 trait_ref: trait_ref.map(|trait_ref| self.lazy(&trait_ref)),
756 EntryKind::Impl(self.lazy(&data))
758 hir::ItemTrait(..) => {
759 let trait_def = tcx.lookup_trait_def(def_id);
760 let data = TraitData {
761 unsafety: trait_def.unsafety,
762 paren_sugar: trait_def.paren_sugar,
763 has_default_impl: tcx.trait_has_default_impl(def_id),
764 super_predicates: self.lazy(&tcx.item_super_predicates(def_id)),
767 EntryKind::Trait(self.lazy(&data))
769 hir::ItemExternCrate(_) |
770 hir::ItemUse(..) => bug!("cannot encode info for item {:?}", item),
775 visibility: self.lazy(&ty::Visibility::from_hir(&item.vis, item.id, tcx)),
776 span: self.lazy(&item.span),
777 attributes: self.encode_attributes(&item.attrs),
778 children: match item.node {
779 hir::ItemForeignMod(ref fm) => {
780 self.lazy_seq(fm.items
782 .map(|foreign_item| tcx.hir.local_def_id(foreign_item.id).index))
784 hir::ItemEnum(..) => {
785 let def = self.tcx.lookup_adt_def(def_id);
786 self.lazy_seq(def.variants.iter().map(|v| {
787 assert!(v.did.is_local());
791 hir::ItemStruct(..) |
792 hir::ItemUnion(..) => {
793 let def = self.tcx.lookup_adt_def(def_id);
794 self.lazy_seq(def.struct_variant().fields.iter().map(|f| {
795 assert!(f.did.is_local());
800 hir::ItemTrait(..) => {
801 self.lazy_seq(tcx.associated_item_def_ids(def_id).iter().map(|&def_id| {
802 assert!(def_id.is_local());
806 _ => LazySeq::empty(),
808 stability: self.encode_stability(def_id),
809 deprecation: self.encode_deprecation(def_id),
811 ty: match item.node {
812 hir::ItemStatic(..) |
817 hir::ItemStruct(..) |
819 hir::ItemImpl(..) => Some(self.encode_item_type(def_id)),
822 inherent_impls: self.encode_inherent_implementations(def_id),
823 variances: match item.node {
825 hir::ItemStruct(..) |
827 hir::ItemTrait(..) => self.encode_item_variances(def_id),
828 _ => LazySeq::empty(),
830 generics: match item.node {
831 hir::ItemStatic(..) |
836 hir::ItemStruct(..) |
839 hir::ItemTrait(..) => Some(self.encode_generics(def_id)),
842 predicates: match item.node {
843 hir::ItemStatic(..) |
848 hir::ItemStruct(..) |
851 hir::ItemTrait(..) => Some(self.encode_predicates(def_id)),
855 ast: match item.node {
856 hir::ItemConst(_, body) |
857 hir::ItemFn(_, _, hir::Constness::Const, _, _, body) => {
858 Some(self.encode_body(body))
862 mir: match item.node {
863 hir::ItemStatic(..) if self.tcx.sess.opts.debugging_opts.always_encode_mir => {
864 self.encode_mir(def_id)
866 hir::ItemConst(..) => self.encode_mir(def_id),
867 hir::ItemFn(_, _, constness, _, ref generics, _) => {
868 let tps_len = generics.ty_params.len();
869 let needs_inline = tps_len > 0 || attr::requests_inline(&item.attrs);
870 let always_encode_mir = self.tcx.sess.opts.debugging_opts.always_encode_mir;
871 if needs_inline || constness == hir::Constness::Const || always_encode_mir {
872 self.encode_mir(def_id)
882 /// Serialize the text of exported macros
883 fn encode_info_for_macro_def(&mut self, macro_def: &hir::MacroDef) -> Entry<'tcx> {
884 use syntax::print::pprust;
886 kind: EntryKind::MacroDef(self.lazy(&MacroDef {
887 body: pprust::tts_to_string(¯o_def.body.trees().collect::<Vec<_>>()),
889 visibility: self.lazy(&ty::Visibility::Public),
890 span: self.lazy(¯o_def.span),
892 attributes: self.encode_attributes(¯o_def.attrs),
893 children: LazySeq::empty(),
897 inherent_impls: LazySeq::empty(),
898 variances: LazySeq::empty(),
907 impl<'a, 'b, 'tcx> IndexBuilder<'a, 'b, 'tcx> {
908 /// In some cases, along with the item itself, we also
909 /// encode some sub-items. Usually we want some info from the item
910 /// so it's easier to do that here then to wait until we would encounter
911 /// normally in the visitor walk.
912 fn encode_addl_info_for_item(&mut self, item: &hir::Item) {
913 let def_id = self.tcx.hir.local_def_id(item.id);
915 hir::ItemStatic(..) |
919 hir::ItemForeignMod(..) |
920 hir::ItemExternCrate(..) |
922 hir::ItemDefaultImpl(..) |
924 // no sub-item recording needed in these cases
926 hir::ItemEnum(..) => {
927 self.encode_fields(def_id);
929 let def = self.tcx.lookup_adt_def(def_id);
930 for (i, variant) in def.variants.iter().enumerate() {
931 self.record(variant.did,
932 EntryBuilder::encode_enum_variant_info,
933 (def_id, Untracked(i)));
936 hir::ItemStruct(ref struct_def, _) => {
937 self.encode_fields(def_id);
939 // If the struct has a constructor, encode it.
940 if !struct_def.is_struct() {
941 let ctor_def_id = self.tcx.hir.local_def_id(struct_def.id());
942 self.record(ctor_def_id,
943 EntryBuilder::encode_struct_ctor,
944 (def_id, ctor_def_id));
947 hir::ItemUnion(..) => {
948 self.encode_fields(def_id);
950 hir::ItemImpl(..) => {
951 for &trait_item_def_id in self.tcx.associated_item_def_ids(def_id).iter() {
952 self.record(trait_item_def_id,
953 EntryBuilder::encode_info_for_impl_item,
957 hir::ItemTrait(..) => {
958 for &item_def_id in self.tcx.associated_item_def_ids(def_id).iter() {
959 self.record(item_def_id,
960 EntryBuilder::encode_info_for_trait_item,
968 impl<'a, 'b: 'a, 'tcx: 'b> EntryBuilder<'a, 'b, 'tcx> {
969 fn encode_info_for_foreign_item(&mut self,
970 (def_id, nitem): (DefId, &hir::ForeignItem))
974 debug!("EntryBuilder::encode_info_for_foreign_item({:?})", def_id);
976 let kind = match nitem.node {
977 hir::ForeignItemFn(_, ref names, _) => {
979 constness: hir::Constness::NotConst,
980 arg_names: self.encode_fn_arg_names(names),
982 EntryKind::ForeignFn(self.lazy(&data))
984 hir::ForeignItemStatic(_, true) => EntryKind::ForeignMutStatic,
985 hir::ForeignItemStatic(_, false) => EntryKind::ForeignImmStatic,
990 visibility: self.lazy(&ty::Visibility::from_hir(&nitem.vis, nitem.id, tcx)),
991 span: self.lazy(&nitem.span),
992 attributes: self.encode_attributes(&nitem.attrs),
993 children: LazySeq::empty(),
994 stability: self.encode_stability(def_id),
995 deprecation: self.encode_deprecation(def_id),
997 ty: Some(self.encode_item_type(def_id)),
998 inherent_impls: LazySeq::empty(),
999 variances: LazySeq::empty(),
1000 generics: Some(self.encode_generics(def_id)),
1001 predicates: Some(self.encode_predicates(def_id)),
1009 struct EncodeVisitor<'a, 'b: 'a, 'tcx: 'b> {
1010 index: IndexBuilder<'a, 'b, 'tcx>,
1013 impl<'a, 'b, 'tcx> Visitor<'tcx> for EncodeVisitor<'a, 'b, 'tcx> {
1014 fn nested_visit_map<'this>(&'this mut self) -> NestedVisitorMap<'this, 'tcx> {
1015 NestedVisitorMap::OnlyBodies(&self.index.tcx.hir)
1017 fn visit_expr(&mut self, ex: &'tcx hir::Expr) {
1018 intravisit::walk_expr(self, ex);
1019 self.index.encode_info_for_expr(ex);
1021 fn visit_item(&mut self, item: &'tcx hir::Item) {
1022 intravisit::walk_item(self, item);
1023 let def_id = self.index.tcx.hir.local_def_id(item.id);
1025 hir::ItemExternCrate(_) |
1026 hir::ItemUse(..) => (), // ignore these
1027 _ => self.index.record(def_id, EntryBuilder::encode_info_for_item, (def_id, item)),
1029 self.index.encode_addl_info_for_item(item);
1031 fn visit_foreign_item(&mut self, ni: &'tcx hir::ForeignItem) {
1032 intravisit::walk_foreign_item(self, ni);
1033 let def_id = self.index.tcx.hir.local_def_id(ni.id);
1034 self.index.record(def_id,
1035 EntryBuilder::encode_info_for_foreign_item,
1038 fn visit_generics(&mut self, generics: &'tcx hir::Generics) {
1039 intravisit::walk_generics(self, generics);
1040 self.index.encode_info_for_generics(generics);
1042 fn visit_ty(&mut self, ty: &'tcx hir::Ty) {
1043 intravisit::walk_ty(self, ty);
1044 self.index.encode_info_for_ty(ty);
1046 fn visit_macro_def(&mut self, macro_def: &'tcx hir::MacroDef) {
1047 let def_id = self.index.tcx.hir.local_def_id(macro_def.id);
1048 self.index.record(def_id, EntryBuilder::encode_info_for_macro_def, macro_def);
1052 impl<'a, 'b, 'tcx> IndexBuilder<'a, 'b, 'tcx> {
1053 fn encode_info_for_generics(&mut self, generics: &hir::Generics) {
1054 for ty_param in &generics.ty_params {
1055 let def_id = self.tcx.hir.local_def_id(ty_param.id);
1056 let has_default = Untracked(ty_param.default.is_some());
1057 self.record(def_id, EntryBuilder::encode_info_for_ty_param, (def_id, has_default));
1061 fn encode_info_for_ty(&mut self, ty: &hir::Ty) {
1062 if let hir::TyImplTrait(_) = ty.node {
1063 let def_id = self.tcx.hir.local_def_id(ty.id);
1064 self.record(def_id, EntryBuilder::encode_info_for_anon_ty, def_id);
1068 fn encode_info_for_expr(&mut self, expr: &hir::Expr) {
1070 hir::ExprClosure(..) => {
1071 let def_id = self.tcx.hir.local_def_id(expr.id);
1072 self.record(def_id, EntryBuilder::encode_info_for_closure, def_id);
1079 impl<'a, 'b: 'a, 'tcx: 'b> EntryBuilder<'a, 'b, 'tcx> {
1080 fn encode_info_for_ty_param(&mut self,
1081 (def_id, Untracked(has_default)): (DefId, Untracked<bool>))
1083 debug!("EntryBuilder::encode_info_for_ty_param({:?})", def_id);
1086 kind: EntryKind::Type,
1087 visibility: self.lazy(&ty::Visibility::Public),
1088 span: self.lazy(&tcx.def_span(def_id)),
1089 attributes: LazySeq::empty(),
1090 children: LazySeq::empty(),
1094 ty: if has_default {
1095 Some(self.encode_item_type(def_id))
1099 inherent_impls: LazySeq::empty(),
1100 variances: LazySeq::empty(),
1109 fn encode_info_for_anon_ty(&mut self, def_id: DefId) -> Entry<'tcx> {
1110 debug!("EntryBuilder::encode_info_for_anon_ty({:?})", def_id);
1113 kind: EntryKind::Type,
1114 visibility: self.lazy(&ty::Visibility::Public),
1115 span: self.lazy(&tcx.def_span(def_id)),
1116 attributes: LazySeq::empty(),
1117 children: LazySeq::empty(),
1121 ty: Some(self.encode_item_type(def_id)),
1122 inherent_impls: LazySeq::empty(),
1123 variances: LazySeq::empty(),
1124 generics: Some(self.encode_generics(def_id)),
1125 predicates: Some(self.encode_predicates(def_id)),
1132 fn encode_info_for_closure(&mut self, def_id: DefId) -> Entry<'tcx> {
1133 debug!("EntryBuilder::encode_info_for_closure({:?})", def_id);
1136 let data = ClosureData {
1137 kind: tcx.closure_kind(def_id),
1138 ty: self.lazy(&tcx.closure_type(def_id)),
1142 kind: EntryKind::Closure(self.lazy(&data)),
1143 visibility: self.lazy(&ty::Visibility::Public),
1144 span: self.lazy(&tcx.def_span(def_id)),
1145 attributes: self.encode_attributes(&tcx.get_attrs(def_id)),
1146 children: LazySeq::empty(),
1150 ty: Some(self.encode_item_type(def_id)),
1151 inherent_impls: LazySeq::empty(),
1152 variances: LazySeq::empty(),
1153 generics: Some(self.encode_generics(def_id)),
1157 mir: self.encode_mir(def_id),
1161 fn encode_attributes(&mut self, attrs: &[ast::Attribute]) -> LazySeq<ast::Attribute> {
1162 // NOTE: This must use lazy_seq_from_slice(), not lazy_seq() because
1163 // we really on the HashStable specialization for [Attribute]
1164 // to properly filter things out.
1165 self.lazy_seq_from_slice(attrs)
1169 impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
1170 fn encode_info_for_items(&mut self) -> Index {
1171 let krate = self.tcx.hir.krate();
1172 let mut index = IndexBuilder::new(self);
1173 index.record(DefId::local(CRATE_DEF_INDEX),
1174 EntryBuilder::encode_info_for_mod,
1175 FromId(CRATE_NODE_ID, (&krate.module, &krate.attrs, &hir::Public)));
1176 let mut visitor = EncodeVisitor { index: index };
1177 krate.visit_all_item_likes(&mut visitor.as_deep_visitor());
1178 for macro_def in &krate.exported_macros {
1179 visitor.visit_macro_def(macro_def);
1181 visitor.index.into_items()
1184 fn encode_crate_deps(&mut self) -> LazySeq<CrateDep> {
1185 fn get_ordered_deps(cstore: &cstore::CStore) -> Vec<(CrateNum, Rc<cstore::CrateMetadata>)> {
1186 // Pull the cnums and name,vers,hash out of cstore
1187 let mut deps = Vec::new();
1188 cstore.iter_crate_data(|cnum, val| {
1189 deps.push((cnum, val.clone()));
1193 deps.sort_by(|kv1, kv2| kv1.0.cmp(&kv2.0));
1195 // Sanity-check the crate numbers
1196 let mut expected_cnum = 1;
1197 for &(n, _) in &deps {
1198 assert_eq!(n, CrateNum::new(expected_cnum));
1205 // We're just going to write a list of crate 'name-hash-version's, with
1206 // the assumption that they are numbered 1 to n.
1207 // FIXME (#2166): This is not nearly enough to support correct versioning
1208 // but is enough to get transitive crate dependencies working.
1209 let deps = get_ordered_deps(self.cstore);
1210 self.lazy_seq(deps.iter().map(|&(_, ref dep)| {
1214 kind: dep.dep_kind.get(),
1219 fn encode_lang_items(&mut self) -> (LazySeq<(DefIndex, usize)>, LazySeq<lang_items::LangItem>) {
1221 let lang_items = tcx.lang_items.items().iter();
1222 (self.lazy_seq(lang_items.enumerate().filter_map(|(i, &opt_def_id)| {
1223 if let Some(def_id) = opt_def_id {
1224 if def_id.is_local() {
1225 return Some((def_id.index, i));
1230 self.lazy_seq_ref(&tcx.lang_items.missing))
1233 fn encode_native_libraries(&mut self) -> LazySeq<NativeLibrary> {
1234 let used_libraries = self.tcx.sess.cstore.used_libraries();
1235 self.lazy_seq(used_libraries)
1238 fn encode_codemap(&mut self) -> LazySeq<syntax_pos::FileMap> {
1239 let codemap = self.tcx.sess.codemap();
1240 let all_filemaps = codemap.files.borrow();
1241 self.lazy_seq_ref(all_filemaps.iter()
1243 // No need to re-export imported filemaps, as any downstream
1244 // crate will import them from their original source.
1245 !filemap.is_imported()
1247 .map(|filemap| &**filemap))
1250 fn encode_def_path_table(&mut self) -> Lazy<DefPathTable> {
1251 let definitions = self.tcx.hir.definitions();
1252 self.lazy(definitions.def_path_table())
1256 struct ImplVisitor<'a, 'tcx: 'a> {
1257 tcx: TyCtxt<'a, 'tcx, 'tcx>,
1258 impls: FxHashMap<DefId, Vec<DefIndex>>,
1261 impl<'a, 'tcx, 'v> ItemLikeVisitor<'v> for ImplVisitor<'a, 'tcx> {
1262 fn visit_item(&mut self, item: &hir::Item) {
1263 if let hir::ItemImpl(..) = item.node {
1264 let impl_id = self.tcx.hir.local_def_id(item.id);
1265 if let Some(trait_ref) = self.tcx.impl_trait_ref(impl_id) {
1267 .entry(trait_ref.def_id)
1269 .push(impl_id.index);
1274 fn visit_trait_item(&mut self, _trait_item: &'v hir::TraitItem) {}
1276 fn visit_impl_item(&mut self, _impl_item: &'v hir::ImplItem) {
1277 // handled in `visit_item` above
1281 impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
1282 /// Encodes an index, mapping each trait to its (local) implementations.
1283 fn encode_impls(&mut self) -> LazySeq<TraitImpls> {
1284 let mut visitor = ImplVisitor {
1288 self.tcx.hir.krate().visit_all_item_likes(&mut visitor);
1290 let all_impls: Vec<_> = visitor.impls
1292 .map(|(trait_def_id, impls)| {
1294 trait_id: (trait_def_id.krate.as_u32(), trait_def_id.index),
1295 impls: self.lazy_seq(impls),
1300 self.lazy_seq(all_impls)
1303 // Encodes all symbols exported from this crate into the metadata.
1305 // This pass is seeded off the reachability list calculated in the
1306 // middle::reachable module but filters out items that either don't have a
1307 // symbol associated with them (they weren't translated) or if they're an FFI
1308 // definition (as that's not defined in this crate).
1309 fn encode_exported_symbols(&mut self) -> LazySeq<DefIndex> {
1310 let exported_symbols = self.exported_symbols;
1312 self.lazy_seq(exported_symbols.iter().map(|&id| tcx.hir.local_def_id(id).index))
1315 fn encode_dylib_dependency_formats(&mut self) -> LazySeq<Option<LinkagePreference>> {
1316 match self.tcx.sess.dependency_formats.borrow().get(&config::CrateTypeDylib) {
1318 self.lazy_seq(arr.iter().map(|slot| {
1320 Linkage::NotLinked |
1321 Linkage::IncludedFromDylib => None,
1323 Linkage::Dynamic => Some(LinkagePreference::RequireDynamic),
1324 Linkage::Static => Some(LinkagePreference::RequireStatic),
1328 None => LazySeq::empty(),
1333 impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
1334 fn encode_crate_root(&mut self) -> Lazy<CrateRoot> {
1335 let mut i = self.position();
1336 let crate_deps = self.encode_crate_deps();
1337 let dylib_dependency_formats = self.encode_dylib_dependency_formats();
1338 let dep_bytes = self.position() - i;
1340 // Encode the language items.
1341 i = self.position();
1342 let (lang_items, lang_items_missing) = self.encode_lang_items();
1343 let lang_item_bytes = self.position() - i;
1345 // Encode the native libraries used
1346 i = self.position();
1347 let native_libraries = self.encode_native_libraries();
1348 let native_lib_bytes = self.position() - i;
1351 i = self.position();
1352 let codemap = self.encode_codemap();
1353 let codemap_bytes = self.position() - i;
1355 // Encode DefPathTable
1356 i = self.position();
1357 let def_path_table = self.encode_def_path_table();
1358 let def_path_table_bytes = self.position() - i;
1360 // Encode the def IDs of impls, for coherence checking.
1361 i = self.position();
1362 let impls = self.encode_impls();
1363 let impl_bytes = self.position() - i;
1365 // Encode exported symbols info.
1366 i = self.position();
1367 let exported_symbols = self.encode_exported_symbols();
1368 let exported_symbols_bytes = self.position() - i;
1370 // Encode and index the items.
1371 i = self.position();
1372 let items = self.encode_info_for_items();
1373 let item_bytes = self.position() - i;
1375 i = self.position();
1376 let index = items.write_index(&mut self.opaque.cursor);
1377 let index_bytes = self.position() - i;
1380 let link_meta = self.link_meta;
1381 let is_proc_macro = tcx.sess.crate_types.borrow().contains(&CrateTypeProcMacro);
1382 let root = self.lazy(&CrateRoot {
1383 name: link_meta.crate_name,
1384 triple: tcx.sess.opts.target_triple.clone(),
1385 hash: link_meta.crate_hash,
1386 disambiguator: tcx.sess.local_crate_disambiguator(),
1387 panic_strategy: tcx.sess.panic_strategy(),
1388 plugin_registrar_fn: tcx.sess
1389 .plugin_registrar_fn
1391 .map(|id| tcx.hir.local_def_id(id).index),
1392 macro_derive_registrar: if is_proc_macro {
1393 let id = tcx.sess.derive_registrar_fn.get().unwrap();
1394 Some(tcx.hir.local_def_id(id).index)
1399 crate_deps: crate_deps,
1400 dylib_dependency_formats: dylib_dependency_formats,
1401 lang_items: lang_items,
1402 lang_items_missing: lang_items_missing,
1403 native_libraries: native_libraries,
1405 def_path_table: def_path_table,
1407 exported_symbols: exported_symbols,
1411 let total_bytes = self.position();
1413 if self.tcx.sess.meta_stats() {
1414 let mut zero_bytes = 0;
1415 for e in self.opaque.cursor.get_ref() {
1421 println!("metadata stats:");
1422 println!(" dep bytes: {}", dep_bytes);
1423 println!(" lang item bytes: {}", lang_item_bytes);
1424 println!(" native bytes: {}", native_lib_bytes);
1425 println!(" codemap bytes: {}", codemap_bytes);
1426 println!(" impl bytes: {}", impl_bytes);
1427 println!(" exp. symbols bytes: {}", exported_symbols_bytes);
1428 println!(" def-path table bytes: {}", def_path_table_bytes);
1429 println!(" item bytes: {}", item_bytes);
1430 println!(" index bytes: {}", index_bytes);
1431 println!(" zero bytes: {}", zero_bytes);
1432 println!(" total bytes: {}", total_bytes);
1439 // NOTE(eddyb) The following comment was preserved for posterity, even
1440 // though it's no longer relevant as EBML (which uses nested & tagged
1441 // "documents") was replaced with a scheme that can't go out of bounds.
1443 // And here we run into yet another obscure archive bug: in which metadata
1444 // loaded from archives may have trailing garbage bytes. Awhile back one of
1445 // our tests was failing sporadically on the macOS 64-bit builders (both nopt
1446 // and opt) by having ebml generate an out-of-bounds panic when looking at
1449 // Upon investigation it turned out that the metadata file inside of an rlib
1450 // (and ar archive) was being corrupted. Some compilations would generate a
1451 // metadata file which would end in a few extra bytes, while other
1452 // compilations would not have these extra bytes appended to the end. These
1453 // extra bytes were interpreted by ebml as an extra tag, so they ended up
1454 // being interpreted causing the out-of-bounds.
1456 // The root cause of why these extra bytes were appearing was never
1457 // discovered, and in the meantime the solution we're employing is to insert
1458 // the length of the metadata to the start of the metadata. Later on this
1459 // will allow us to slice the metadata to the precise length that we just
1460 // generated regardless of trailing bytes that end up in it.
1462 pub fn encode_metadata<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
1463 cstore: &cstore::CStore,
1464 link_meta: &LinkMeta,
1465 exported_symbols: &NodeSet)
1468 let mut cursor = Cursor::new(vec![]);
1469 cursor.write_all(METADATA_HEADER).unwrap();
1471 // Will be filed with the root position after encoding everything.
1472 cursor.write_all(&[0, 0, 0, 0]).unwrap();
1474 let (root, metadata_hashes) = {
1475 let mut ecx = EncodeContext {
1476 opaque: opaque::Encoder::new(&mut cursor),
1478 link_meta: link_meta,
1480 exported_symbols: exported_symbols,
1481 lazy_state: LazyState::NoNode,
1482 type_shorthands: Default::default(),
1483 predicate_shorthands: Default::default(),
1484 metadata_hashes: Vec::new(),
1487 // Encode the rustc version string in a predictable location.
1488 rustc_version().encode(&mut ecx).unwrap();
1490 // Encode all the entries and extra information in the crate,
1491 // culminating in the `CrateRoot` which points to all of it.
1492 let root = ecx.encode_crate_root();
1493 (root, ecx.metadata_hashes)
1495 let mut result = cursor.into_inner();
1497 // Encode the root position.
1498 let header = METADATA_HEADER.len();
1499 let pos = root.position;
1500 result[header + 0] = (pos >> 24) as u8;
1501 result[header + 1] = (pos >> 16) as u8;
1502 result[header + 2] = (pos >> 8) as u8;
1503 result[header + 3] = (pos >> 0) as u8;
1507 hashes: metadata_hashes,
1511 pub fn get_repr_options<'a, 'tcx, 'gcx>(tcx: &TyCtxt<'a, 'tcx, 'gcx>, did: DefId) -> ReprOptions {
1512 let ty = tcx.item_type(did);
1514 ty::TyAdt(ref def, _) => return def.repr,
1515 _ => bug!("{} is not an ADT", ty),